Howard Stern received a rock-star welcome to prime-time Monday night as he joined the judges' panel of "America's Got Talent."

The notorious radio man was high-fived and hugged as he walked through the packed audience to take his seat alongside Sharon Osbourne and Howie Mandel for the premiere of the talent contest's seventh season.

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"I don't know who's responsible for this, but they should be fired immediately," Stern said at the top of the show, referring to NBC's decision to fill Piers Morgan's vacant seat with him.

Stern quickly took the reins, effortlessly ushering the two-hour program along through quick exchanges with the contestants and his fellow judges, with whom he appeared to have a strong, playful rapport.

Outrageous Howard Stern Won't Hold Back on New Show

Howard Stern won't hold back his opinions when he debuts as a judge on Season 7 of NBC's "America's Got Talent" but the controversial radio host says he won't turn "America's Got Talent" into another "Howard Stern Show." Stern replaces Piers Morgan while fellow judges Sharon Osbourne and Howie Mandel return. "America's Got Talent" premieres May 14 on NBC at 8/7c. (Published Friday, May 11, 2012)

He also made an effort to offer some kind words to the contestants he rejected.

"That was awful," he told one singer whose act invited more laughter from the audience than applause. "But you know that, don't you? You're a nice enough guy," he said.

And he played nicely with the children.

When a 7-year-old, who sang with her father, asked—with a big dose of spunk—what happened to Stern's father, he shot back instantly.

"You don't want to know," he told her, matching her attitude, before approving the act.

Earlier in the program, when a woman covered with cockatiels took the stage, he quizzed her on her act and her life trying to quickly size her up as he does with his guests on "The Howard Stern Show."

"You're a vegetarian, aren't you?" he asked after establishing that her patterned shirt was intended to mask the stains that come with her bird act. "You'd rather die than eat your own birds," he continued.

He gave the bird lady the disapproving "X," as he did to good number of the night's performers, but not with any ruthlessness or profanity some critics feared he might inject into prime-time.

Osbourne and Mandel contributed their own antics to the show—Osbourne cringing and turning away as a man steadied the arrow he was about to fire into a balloon held between his assistant's teeth; and Mandel singing along, dancing in his seat and occasionally offering mocking impressions of contestants. But it was Stern who dominated the show.

Some acts that will make it to the next round in Las Vegas include a man who builds and plays his own garage-sized instruments, two father-daughter musical acts, a couple dance teams and a young girl who twirled and tumbled through the air in an aerial act.

The rejected crew includes a man who pierced his own face on stage, several singers and a magician-stripper, whom Stern criticized for having "man boobs."

The NBC competition, which offers a $1 million prize to the most talented act, continues next week at 8 p.m. ET.